LCD backlight repair
Success! Replaced the 4 and we got light, and a functional TV again. This was saved from a customer that was tossing it and it was bigger and newer than the one I had in the kids room so blammo. One issue I found is that the LED;s are specific in shape to diffuse properly in the little diffuser lenses. I put an edge mount LED in place (all I had in the bin) and they are not the same shape so I have 4 brighter spots on the screen now. The LED's are 1W/3V 3 millimeter square surface mount, (3030?) no lens. They shoot up into an inverted cone in the diffuser lens and then radiate the light out the side, no direct illumination to the LCD panel.
They obviously are polarized so you need to make sure you got the right orientation: the anode/cathode pads are different sizes and that matches the solder mask so it should be easy to see its direction. There are 2 little test points outboard of each LED, a DMM in continuity will make the LED barely glow if its good. Be careful, the test points were opposite what the orientation of the LEDs are for some reason, I installed all 4 backwards the first time going off the test points as my LEDs didnt have the same solder pad shapes of the originals. The LED's themselves are bought in strips of 100 for about 8 bucks.
@67Dart273 the info was found on youtube of all places. Seems a popular repair for the crafty folks, then looking up the replacement parts and finding the specs of the LED's themselves. The feeds were 37V so i figured the forward voltage of the LEDs were 3.7v as they are in series, strips of 10. You can buy them in continuous ribbons with cut points between LED's for a custom array. Hardest part was getting everything apart (30 bezel screws and snap tabs) and then aligning the 2 diffuser sheets onto the lugs under the very fragile LCD plate glass that's still hinged to the chassis by the 4-6 ribbon cables. Everything snaps together then you screw the bezel down to lock everything in place. You probably need a hot air station to resolder the SMD LEDs but someone laid the strip on a hot plate (they make such things!) and was able to melt the solder from the back as the ribbon is metal backed for heatsink duties. Seriously, if you get PLUTO stream (free), you can cut the cord as there are hundreds of channels on this stream, just use an outdoor antenna for local news if your in range. I was watching Africa Cup soccer last night then the at home college boy was streaming his youtube music playlist to it and hooking up the ol' PS3 to it for some midnight NHL15 action.
Success! Replaced the 4 and we got light, and a functional TV again. This was saved from a customer that was tossing it and it was bigger and newer than the one I had in the kids room so blammo. One issue I found is that the LED;s are specific in shape to diffuse properly in the little diffuser lenses. I put an edge mount LED in place (all I had in the bin) and they are not the same shape so I have 4 brighter spots on the screen now. The LED's are 1W/3V 3 millimeter square surface mount, (3030?) no lens. They shoot up into an inverted cone in the diffuser lens and then radiate the light out the side, no direct illumination to the LCD panel.
They obviously are polarized so you need to make sure you got the right orientation: the anode/cathode pads are different sizes and that matches the solder mask so it should be easy to see its direction. There are 2 little test points outboard of each LED, a DMM in continuity will make the LED barely glow if its good. Be careful, the test points were opposite what the orientation of the LEDs are for some reason, I installed all 4 backwards the first time going off the test points as my LEDs didnt have the same solder pad shapes of the originals. The LED's themselves are bought in strips of 100 for about 8 bucks.
@67Dart273 the info was found on youtube of all places. Seems a popular repair for the crafty folks, then looking up the replacement parts and finding the specs of the LED's themselves. The feeds were 37V so i figured the forward voltage of the LEDs were 3.7v as they are in series, strips of 10. You can buy them in continuous ribbons with cut points between LED's for a custom array. Hardest part was getting everything apart (30 bezel screws and snap tabs) and then aligning the 2 diffuser sheets onto the lugs under the very fragile LCD plate glass that's still hinged to the chassis by the 4-6 ribbon cables. Everything snaps together then you screw the bezel down to lock everything in place. You probably need a hot air station to resolder the SMD LEDs but someone laid the strip on a hot plate (they make such things!) and was able to melt the solder from the back as the ribbon is metal backed for heatsink duties. Seriously, if you get PLUTO stream (free), you can cut the cord as there are hundreds of channels on this stream, just use an outdoor antenna for local news if your in range. I was watching Africa Cup soccer last night then the at home college boy was streaming his youtube music playlist to it and hooking up the ol' PS3 to it for some midnight NHL15 action.
